Here are some of my ideas about the 1960 scenario
The sides would be
1 USA
2 USSR
3 NATO (Capital in London instead of historical Brussels so it can fight on if mainland Europe falls)
4 WARSAW
5 SEATO
6 Non aligned Movement (capital in India)
7 PRC
8 Commie Rebels (nationalist Chinese Pieces)
Basically, the nonaligned movement and the PRC would be neutral powers. The game would have an individual winner based on which country had the most of their national objectives fulfilled. Both of the free agent powers would have national objectives that would put them at odds with the US or USSR’s blocs. For instance, China would have national objectives for taking Taiwan from the allies and for taking Mongolia from the Soviets. They would be free to declare war on whoever they chose though they could also be attacked by one of the two main power blocs.
I think I’d allow the USSR/WARSAW Pact and the communist Chinese to support communist rebel movements in the recently decolonized territories of the world. These units (infantry only) would lay dormant in the territory until their masters decided to launch a general uprising at which point they would attack any units there and, if successful, would seize the territory for their sponsor. Non communist forces could target these rebels prior to that but any that survive the first cycle of combat would escape back into the countryside. The PRC and the USSR should be able to sponsor rebel movements in the same territory if they are feeling competitive.